Puffing steam out vents

[04fxdwgi25]

Question: Has that been run in salt / brackish water? If so, that aluminum manifold will not hold up in those conditions and can corrode the water passages pretty quickly on a raw water cooled engine.

Other than that, some of the cyls (6 and 8) show signs of head gasket possibly leaking by, allowing water into cyls.

 

[Lou C]

That doesn’t look good….a lot of blow by. I’d do a compression test and a leak down test. What’s the oil look like?

 

[a70eliminator]

That doesn’t look good….a lot of blow by. I’d do a compression test and a leak down test. What’s the oil look like?

Hmmmm I wonder why lol

 

[Lou C]

Well your air pressure test was good, right? Now before this happened did this engine consume oil at all? You can expect some blow by from an engine used in this application because there is no PCV to pull the vapors out. Now really thinking about it, you MIGHT still have moisture in the oil that has to burn off….so as long as the oil looks good you might take it for a run out on the water and see if the steaming is greatly reduced. Like I said there will always be some due to the lack of a positive crankcase ventilation valve. Still, I’d do a hot compression test to have a baseline. My old 1988 4.3 V6 shows 160-170 psi. I do one at the end of each season plus an oil analysis.

 

[a70eliminator]

Lou that video was shot Fri. and was the reason for pulling heads, put them back on Sat. with new gaskets, still have some stuff to re-assemble before I can start the engine.
Im like a farmer with a stuck tractor, he don't eat till it's unstuck.
And to answer your question the motor never had blowby & oil was always clean & full the engine looks surprisingly clean inside definately not original to the 1984 boat, oh and I've only had it since last year so still pretty new to me.

 

[Lou C]

Ohhh I misunderstood the time frame there; that vid was from before you did the cyl head work! Well the engine did look really pretty good maybe you caught it at the beginning of a head gasket leak. Well keep running it; based on my experience as long as your sealing surfaces were clean & level and bolt holes were clean & you got accurate torque on the cyl heads it should be fine.

 

[ROY WILLIAMS]

First run of season, block and manifolds were drained for winter, ran all last year without incident, invoiced the steam at home in driveway on hose but disregarded it for moisture burning off.
Took on lake and vents spitting out droplets of water after running awhile, engine temp normal powers up 4800 rpm idles nice but now oil is completely milky but level ok on dipstick.
Only thing that changed over winter was new riser gaskets, new thermostat.
Is it possible a riser gasket seeping could cause this?
I pulled the intake and heads, underside of v/c's and lifter valley all milkshake, head gaskets looked ok, in stumped.

engine antifreeze 60% distilled water 40% coolant ... engine antifreeze coolant and the water ocean ?

 

[a70eliminator]

engine antifreeze 60% distilled water 40% coolant ... engine antifreeze coolant and the water ocean ?

No ocean in Northeast Ohio lol
Freshwater, open loop no rad.

 

[ROY WILLIAMS]

No ocean in Northeast Ohio lol
Freshwater, open loop no rad.

ROY WILLIAMS ENGINE 1978 , 470 Mercrusier ANTIFREEZE 60% DISTILLED WATER 40% .. RADIATOR . MARCH 2025 !!! ENGINE VERY NOTICE !

FRESHWATER DAMAGED ENGINE ..........NO RADIATOR .

 

[Lou C]

PS that boat looks like new for a 1984
Freshwater must be a treat
Nothing lasts like that here in the salt pond
My boatyard guys are amazed I'm still running an '88 Cobra, that has sat in salt water every summer since I bought it 23 years ago.
The only parts needing replacement due to salt use were the exhaust manifolds (my 4.3 is on its 4th exhaust system) and the ram rods for the trim system that got pitted and rotted at the ends...no leaks in the transom like on some Merc drives....no rotted steering arm....etc....
So I gotta think...even with OMC's not so good reputation...they must have done something right!
Having said that I bought a nice freshwater used transom mount from the midwest that I harvest parts off of when I need em....

 

[a70eliminator]

PS that boat looks like new for a 1984
Freshwater must be a treat
Nothing lasts like that here in the salt pond
My boatyard guys are amazed I'm still running an '88 Cobra, that has sat in salt water every summer since I bought it 23 years ago.
The only parts needing replacement due to salt use were the exhaust manifolds (my 4.3 is on its 4th exhaust system) and the ram rods for the trim system that got pitted and rotted at the ends...no leaks in the transom like on some Merc drives....no rotted steering arm....etc....
So I gotta think...even with OMC's not so good reputation...they must have done something right!
Having said that I bought a nice freshwater used transom mount from the midwest that I harvest parts off of when I need em....

Loved my 5.8 cobra, shift cable alignment not a big deal bullet proof drive gears long as theres lube & we both know that story.

 

[Lou C]

Yep I had very good luck with the Cobra. I’ve also got a spare drive that I’m going to get rebuilt; the original which was last resealed in 2006 is still shifting fine…

 

[a70eliminator]

Yep I had very good luck with the Cobra. I’ve also got a spare drive that I’m going to get rebuilt; the original which was last resealed in 2006 is still shifting fine…

Impeller changes are a snap & I liked the dipstick.

 

[cyclops222]

You do realize that SOME head gaskets need to be re-torqued after a few minutes of being heated up fully ?
I always did a warmed up check of a couple of bolts. Then did a 1 or 2 minute WOT run and a retorque check. Some needed retightening.

 

[Lou C]

Unless you use a Fel Pro permatorque

 

[nola mike]

Unless you use a Fel Pro permatorque

IIRC my vortec didn't need retorque; the head bolts were TTY/ torque + 90' or something.

 

[Lou C]

I definitely didn’t have to retorque the ones on my pre Vortec; the gaskets seem to be high quality; I think the bigger thing is that you have to clean out the cylinder head bolt holes in the block (thread chaser) and really clean the threads of the head bolts. Mine were rusty so I would up replacing them with ARP head bolts.